In this first history lesson, couldn't they have triangulated a bit more than that? I can think of a couple methods:<P>1) Two stations receive the signal, but at slightly different bearings. This produces a triangle (two corners being the stations and the third the source).<P>2) Calculate the velocity at which the Earth was passing through the signal. Assume both source and receiver are at rest with respect to one another; then successively remove the Earth's velocity relative to Sun, stellar cluster, galactic arm, and galaxy to see if anything comes up zero. This gives you a range.<P>3) Determine if there was a Doppler change during the time spent in the signal.<P>I dunno... I kinda almost flunked my Signals course stream.<P>------------------Crewman: "Sir! An enemy ship is approaching! Can't scan its defenses!"Captain: "Very well... ARM PHASE CANNON!"-------------------------------------------------------------------------De enemies just ran roughshod over DeMatt...

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by DeMatt:<B>In this first history lesson, couldn't they have triangulated a bit more than that? </B><HR></BLOCKQUOTE><P>They did triangulate, however a few problems existed. First, it was a tight-beam signal and not a broadcast signal, giving them a very short amount of time and a short distance (relative) between reception points. Plus there were only two recievers available to pick up a signal that weak. Third, the signal had been badly distorted along it's journey. The whole combination, plus the fact the the source of the signal had moved quite a bit in the 10 billion years since being sent, made it all but impossible to get an absolute fix.<P>I'd keep going, but signals class did indeed suck and I'm skating on memory here. Someone well versed in signal theory might just as well pick me apart or back me up. <IMG SRC="http://www.keenspace.com/forums/wink.gif"><P>------------------Brian Westaka Tirdun<A HREF="http://mailto:tirdun@yahoo.com" TARGET=_blank>tirdun@yahoo.com</A><A HREF="http://farawaystars.keenspace.com" TARGET=_blank>farawaystars.keenspace.com</A>

Okay, points responded to within the comic... I should have waited to see what would happen.<P>Of course, for the Earth's signal to be at all legible ten billion lightyears from there, I guesstimate that the signal (assuming it is tightbeamed like mad) would roughly... hmm...<P>1) assume angular coverage of signal is 0.0001% of sphere<P>2) assume maximum visible range of Sun is 1000 lightyears<P>3) multiply<P>... that the signal, over its duration, would outshine the Sun by a factor of 10.<P>That's a lot of power.<P>------------------Crewman: "Sir! An enemy ship is approaching! Can't scan its defenses!"Captain: "Very well... ARM PHASE CANNON!"-------------------------------------------------------------------------De enemies just ran roughshod over DeMatt...

Or the guys designing it realized it wouldn't matter one bit either way and it puts out enough juice to toast bread. <P>------------------Brian Westaka Tirdun<A HREF="http://mailto:tirdun@yahoo.com" TARGET=_blank>tirdun@yahoo.com</A><A HREF="http://farawaystars.keenspace.com" TARGET=_blank>farawaystars.keenspace.com</A>